Packages formed from plastic, polymeric film material have found widespread application in the market place for convenient and efficient packaging of all manner of food and non-food products. Packages of this nature typically are formed by folding and sealing a web of polymeric material to form a package body having front and rear package panels, with the package panels joined to each other at margins thereof. Depending upon the method of formation, the front and rear package panels may be joined to each other either by folded portions of the package body, or at seals (typically heat seals) joining the package panels to each other.
Efficient packaging of all manner of products and articles can be effected through use of a so-called form, fill and seal apparatus, which is configured to permit end-to-end formation of packages attendant to filling each package with the desired contents. U.S. Pat. No. 4,909,017, hereby incorporated by reference, illustrates an apparatus of this nature, showing the manner in which packaging are intermittently formed and advanced attendant to filling of each of the packages.
For many applications it is desirable to form a gusseted package, that is, providing the package with inwardly-extended, pleat-like gussets at one or more margins of the package body. One type of package which can advantageously facilitate retail display is sometimes referred to as a “stand up” or bottom-gusseted package, that is, a package having an inwardly extending gusset at the bottom of the package body. By virtue of the gusset provided at the bottom of the package, the package to be readily displayed in an upstanding or self-standing orientation for promoting efficient display for consumer selection from a store shelf or other display area.
US Patent Publications No. 2014/0161373, and No. 2014/0294326, both of which are hereby incorporated by reference, disclose a particularly efficient method for forming a bottom-gusseted package, by which technique a bottom gusset for each package is positioned transversely of a longitudinal axis of a web of material from which the package is formed. Notably, this formation method facilitates bottom gusset package formation in conjunction with a form, fill and seal apparatus to promote cost-effective and versatile use of bottom-gusseted, stand-up packages.
Experience has shown that attendant to package formation in accordance with the above-referenced patent publications, it can be desirable to provide an arrangement by which a sleeve from which each package gusset is formed is maintained in a generally closed or folded configuration during package formation and filling. In particular, each package gusset is formed from a web of material comprising a lamination, such as a co-extrusion, of two different polymeric materials which exhibit differing heat-sealing characteristics. Gusset formation is effected by folding and cutting the web of material to provide individual sleeves which form the bottom gusset of each respective package. To facilitate package formation, each sleeve, and ultimately each gusset, includes a non-heating surface at the interior of the gusset to permit the gusset to splay or open, while the exterior surface is subject to heat-sealing, thus facilitating package formation and filling such as in conjunction with a form, fill and seal apparatus.
The present invention is directed to a method of forming individual sleeves each having an exterior surface that can be heat-sealed for forming the bottom gusset of a package, while each sleeve is temporarily maintained in a closed configuration during package formation. Thereafter, attendant to package formation and filling, the sleeve which provides the bottom gusset is readily opened or splayed apart so that the package has the desired stand-up configuration.